sanjay gupta. sanjay, we all want to avoid this flu virus, so where does it live? on the surfaces, in the air? in other words, how does it spread? >> yeah, you know, it's kind of everywhere. and that's part of the reason it becomes so widespread. certainly in the air, is how you -- people typically think about this. people coughing and sneezing. these microscopic droplets, potentially causing infection, but it can also live on surfaces. it usually lives on a surface for about eight hours, wolf. so if you've been typing on a keyboard or opening a door or something like that, you can potentially, you know, get it that way. you also, without knowing it, wolf, touch your hand to your face hundreds of times a day, and that can be a route of transmission. wolf, one thing i should point out, a day or so before you even get sick, if someone's going to get the flu, they become contagious. and that's important to point out, because we look for the people who are sick and try to avoid them, but really, anybody can potentially be spreading the flu. you've got to always be mind